This invention relates to a recording control apparatus and a recording control method for controlling the data to be recorded in a rewritable non-volatile memory and also to a recording apparatus integral with a camera that utilizes a rewritable non-volatile memory as auxiliary recording apparatus.
Rewritable non-volatile memories or flash memories are well known as recording mediums. Flash memories have a characteristic that the contents thereof are not erased if power supply is stopped and they can be integrated to provide a high memory capacity. Additionally, since flash memories are small and lightweight, they can suitably be used as auxiliary recording apparatus of portable type electronic appliances. Techniques are known to exploit the advantages of flash memories so as to preserve only the management data of an optical disc recording apparatus in a flash memory and make the optical disc completely accessible (see, inter alia, Jpn. Pat. Appln. Laid-Open Publication No. 11-242563).
Large capacity flash memories have been developed in recent years to raise the data transfer rate to a level several times as high as the standard bit rate of optical discs. It is also technically possible to record a large volume of data in a flash memory for the purpose of storing movies and still images.
Meanwhile, flash memories are accompanied by problems including that they can be degraded when a part thereof is used intensively and that they are not fully bit-alterable and hence it is not possible to write new data unless the existing data are erased. Flash memories are equipped with a dedicated file system that is referred to as flash file system in order to dissolve the above identified problems. With a flash file system, a flash memory is divided into a plurality of erase blocks and erasures are uniformly distributed among the erase blocks in order to avoid a situation where written data are not concentrated in particular erase blocks while operations of garbage collection are conducted to dispose unnecessary data accumulated in erase blocks. It takes about a second in average and ten seconds in the worst case per block for such an erasing process.
Since a flash memory is small and lightweight and yet has a large capacity, it can be carried with ease. However, since a long time is necessary for erasing processes, it is difficult to record the stream data obtained by picking up a moving image by means of a video camera in a flash memory.
On the other hand, images picked up by video cameras are more often than stored on optical discs such as DVDs. However, the recording unit of flash memories is larger than an EEC block that is the recording unit of optical discs and hence the conversion processing time is long for the application format and the file system of an optical disc designed on the basis of the ECC block.
Besides, if picked up images are stored on a DVD of near future that are expected to employ a holographic disc structure, for example, a disc showing a recording density 8 times higher than the recording density of currently available DVDS, the recording unit of a flash memory is smaller than the write unit of a recording page showing the 8 times higher recording density and hence the write conversion processing time of the application format and the file system from a DVD to a high density disc is longer if the write conversion is conducted on the assumption of high density recording using a recording page writing unit of a recording density eight times higher than that of an ECC block of a DVD with the standard recording density.
In view of the above-identified circumstances, it is desirable to provide a recording control apparatus and a recording control method for efficiently executing the recording process of a flash memory and the transfer process of data recorded in a flash memory to an optical disc along with a recording apparatus integral with a camera using a flash memory as auxiliary recording device.